Many electronic applications require the detection of a magnetic field. Dual drain magnetic field effect transistors (MAGFETs) are known, and are very effective for determining the strength of a magnetic field. In some cases, MAGFETs are also used to detect the absence and presence of a magnetic field. However, because of the sensitivity of a conventional MAGFET there is a limit on the smallest detectable magnetic field.
Although the sensitivity of the MAGFET can be increased by introducing multiple gates to generate a longitudinal potential gradient along the channel, as for example detailed in F. J. Kub and S. S. Scott, Multiple-gate split-drain MOSFET magnetic-field sensing device and amplifier, IEDM Technical Digest., IEEE, New York, 1992, pp. 517–520, such modifications typically lead to substrate bias. Furthermore, due to velocity saturation, the improvement of the sensitivity by this approach is limited.
Accordingly, there is a need for a more sensitive magnetic field detector and method.